/Engine/Plugins/Online/OnlineFramework/Source/Lobby/Public/LobbyBeaconHost.h
Update the party leader for a given player
void UpdatePartyLeader ( const [FUniqueNetIdRepl](API\Runtime\Engine\GameFramework\FUniqueNetIdRepl) & PartyMemberId, const [FUniqueNetIdRepl](API\Runtime\Engine\GameFramework\FUniqueNetIdRepl) & NewPartyLeaderId )